Horticulture Tips for Peonies
Gardeners love perennials for the fact they usually plant once and enjoy them for years. Peonies have been known to thrive in the same garden spot for over 100 years when established properly (and they are deer-resistant!). They love humus-rich neutral soil (6.5 pH) that is evenly moist, but it also must be well drained. Peonies do not like being disturbed or transplanted, so here are some guidelines to care for new or existing plants.
Peonies are usually sold as bare-root tubers, and you should select plants with at least three to five ‘eye’ buds. Fall planting assures the best success rate, and October is ideal for our area. Select a location with four hours of sun or more, protected from strong winds, and away from other competing plant roots such as large shrubs or trees. Loosen soil two feet deep and two feet across for each plant. Amend with compost and one cup of bonemeal. This will seem like a lot of work, but remember, this will be the first and hopefully LAST time you will ever touch this plant again! It is important to tamp the soil firmly before placing the tuber in the hole because peonies will struggle if planted too deep. Eye buds should just barely be exposed and roots one to two inches deep below soil line. Back fill and water. If the plant settles deeper, lift and reset. Mulch lightly with pine straw or loose wood chips in the first year for winter protection, and remove in early spring. Established plants do not need mulching.
Contrary to many other perennials, peonies do not stop blooming because of overcrowded roots. If you have plants that never bloomed or have stopped blooming, the cause could be they are planted too deep, too much mulch, shade, wet feet, or spring killing frost. Fall is the ideal time to lift and move your plant, using garden forks to carefully pry from garden soil. This will be a major task if it’s an older plant, as the tubers will be large and entwined. Cut foliage off and gently remove soil to expose eyes. Keep as much soil on roots and plant ‘eyes’ at ground level. This trauma may delay blooming another year, but do not fertilize at this time. Distinctive seed pods appear after peony blooms are spent.
Plants usually benefit from staking, and a simple ring stand works well. Place the ring over the plant, and allow it to grow up through the wire. Some varieties have long-stemmed flowers and an additional stake may be needed.
Go light on mulch around the plant, and do not mulch the crown. If soil is poor, compost or bonemeal can be spread at the foliage drip line after blooms are deadheaded in early summer. Peonies are light feeders, and over-fertilizing will encourage foliage, not flowers. Feed once every three years. For fall maintenance remove all stems one inch above ground level, and do not compost leaves.
—Laurie McMinn, Historic Grounds Supervisor